Field
The present disclosure relates generally to voltage regulating devices, and more specifically to techniques for reducing interferences between voltage regulators.
Background
Voltage regulators are in widespread use today for maintaining or regulating the voltage at a desired level in a circuit or a portion of a circuit. A voltage regulator may be of a linear type, such as a low dropout regulator, or a non-linear type, such as a switching regular.
A linear voltage regulator offers the advantage of an output with reduced noise in their direct current (DC) output, but come with disadvantage of inefficient power usage. In contrast, a non-linear regular offers the advantages of efficient power usage but the disadvantages of added noise, relative to a linear voltage regulator.
Currently, one method to regulate voltage is to use a non-linear voltage regular in series with two or more linear voltage regulators. In this approach, the non-linear voltage regular is used to perform most of the voltage regulation (that is convert the battery voltage to a value that is very close to the required load voltage) so to take advantage of the power efficiency of the non-linear voltage regular. Linear voltage regulators, which have better noise performance, are then used to perform the final ‘fine regulation’ of the voltage.
A shortcoming in the above approach is that a change in the load in one linear voltage regulator adversely affects the performance of the other linear voltage regulator(s) due to a generated transient current. This current causes cross-regulation interference between the linear voltage regulators, resulting in added noise and other inefficiencies in the operations of the other voltage regulator(s) and hence the overall system.
Accordingly, there is a need in the art for reducing the cross-regulation interference between the linear voltage regulators.